Hodson District

Location
This district is in the Sierra Nevada west gold belt in southwestern Calaveras County a few miles west of Copperopolis. A belt of lode-gold deposits extends from the site of the old town of Hodson northwest through Salt Springs Valley, a distance of about 10 miles. At one time this district was also known as the Felix district.

History
Small-scale placer mining probably was done here during the gold rush, and the mining of rich surface pockets soon followed. The district was highly productive during the 1890s and early 1900s when the Royal mine and other properties were worked on a large scale. The 120-stamp mill at the Royal mine, erected in 1903, was one of the largest mills in California. The mines were active again during the 1930's and early 1940s. Copper ore from Copperopolis was treated at the Mountain King Mill during World War II. More recent exploration work, including diamond drilling, has been done in the district, but very little of it has been gold mining.

GeologyOn the west side of the mineralized belt are northwest-trending beds of slate of the Mariposa Formation (Upper Jurassic). Metavolcanic rocks, chiefly massive greenstones and amphibolite of the Logtown Ridge Formation (Upper Jurassic), are on the east. The central portion has been intruded by numerous serpentinized bodies in or adjacent to the northwest-trending Hodson fault zone.

Ore Deposits
The deposits consist of large low-grade bodies of mineralized schist and greenstone known as "gray ore," which contain some disseminated free gold, auriferous pyrite and minor amounts of other sulfides. The deposits are associated with the Hodson fault. One of the larger gray ore bodies is several thousand feet long, 500 feet wide, and has been mined to an inclined depth of several thousand feet. Some high-grade pockets have been taken from quartz veins and stringers containing free gold and sulfides.